View single post by Esprit2
 Posted: 02-15-2017 12:55 am
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Joined: 05-01-2005
Location: Minneapolis, Minnesota USA
Posts: 337
Bfitz241 wrote:
(Snip)... I've been driving the car and it has an almost imperceptible misfire at the top of the idle circuit.I'm not totally clear on what you're saying. It has a slight miss/ stumble at around 3200 rpm? If so, that's the idle circuit running out of fuel capacity before the mains take over, and usually, playing with the idle air corrector will not fix that. It needs more fuel, and that's done with the idle jets.

If you're bent on tweaking the idle air corrector, then note that they are not listed in any logical order... purely random. The order is as follows:

Idle Air Corrector Jet Sizes:
7850.5 .. Leaner, going down the list gets richer.
7850.1 .. Normal
7850.3 .. Normal
7850.6 .. 6 & .7 are very similar, almost interchangeable
7850.7 .. The 9XX likes 7
7850.8 .. Richest

Changes to the idle jet and idle air corrector do influence one another, so it's possible that going richer on the air corrector will solve a marginal stumble at around 3200 rpm, but don't count on it. Try playing with the air correctors if you wish, but don't be surprised if, in the end, it's a jet change that eliminates the stumble.

Regards, and good luck,
Tim Engel

Last edited on 02-15-2017 10:41 pm by Esprit2